Dahl S G, Strandjord R E
Clin Pharmacol Ther. 1977 Apr;21(4):437-48. doi: 10.1002/cpt1977214437.
Plasma concentrations of chlorpromazine and its sulfoxide were measured after single intramuscular, single oral, and multiple oral doses of chlorpromazine. In four out of nine patients, intramuscular doses gave stable chlorpromazine plasma levels which were maintained for 12 hr or longer. Chlorpromazine sulfoxide was found in plasma from all patients after oral doses but not after intramuscular doses, which indicates that sulfoxidation took place presystemically. The biologic availability of single oral doses relative to single intramuscular doses ranged from 10 to 69%, and was on average 32%. After 33 days of oral dosing, the plasma levels of chlorpromazine were on average 37% lower than might have been predicted from the single oral dose curves. This was not due to decreased biologic t 1/2 of chlorpromazine, but apparently to a decrease in the biologic availability by oral administration, possibly by increased presystemic metabolism.
在单次肌内注射、单次口服和多次口服氯丙嗪后，测定了血浆中氯丙嗪及其亚砜的浓度。9名患者中有4名，肌内注射剂量可使氯丙嗪血浆水平稳定，并维持12小时或更长时间。口服给药后，所有患者的血浆中均发现了氯丙嗪亚砜，但肌内注射后未发现，这表明硫氧化发生在体循环前。单次口服剂量相对于单次肌内注射剂量的生物利用度范围为10%至69%，平均为32%。口服给药33天后，氯丙嗪的血浆水平平均比单次口服剂量曲线预测的低37%。这不是由于氯丙嗪的生物半衰期缩短，而是显然由于口服给药后生物利用度降低，可能是由于体循环前代谢增加。
